Surgical masks as good as respirators for flu and respiratory virus protection

UT Southwestern Medical Center

DALLAS –
Sept. 6, 2019 – Researchers may finally have an answer in the long-running
controversy over whether the common surgical mask is as effective as more
expensive respirator-type masks in protecting health care workers from flu and
other respiratory viruses.

Study
published in JAMA

A study
published in JAMA compared the ubiquitous surgical (or medical) mask, which
costs about a dime, to a less commonly used respirator called an N95,
which costs around $1. The study reported “no significant difference in the
effectiveness” of medical masks vs. N95 respirators for prevention of
influenza
or other viral respiratory illness.

“This study
showed there is no difference in incidence of viral respiratory transmission
among health care workers wearing the two types of protection,” said Dr. Trish
Perl, Chief of UT Southwestern’s Division of Infectious Diseases and Geographic
Medicine and the report’s senior author. “This finding is important from a
public policy standpoint because it informs about what should be recommended
and what kind of protective apparel should be kept available for outbreaks.”

Medical
personnel – in particular nurses, doctors, and others with direct patient
contact – are at risk when treating patients with contagious diseases
such as influenza (flu). A large study conducted in a New York hospital system
after the 2009 outbreak of H1N1, or swine flu, found almost 30 percent
of health care workers in emergency departments contracted the disease
themselves, Dr. Perl said.

During that
pandemic, the U.S. Centers for Disease Control and Prevention (CDC)
recommended using the tighter-fitting N95 respirators, designed to fit closely
over the nose and mouth and filter at least 95 percent of airborne particles,
rather than the looser-fitting surgical masks routinely worn by health care
workers, Dr. Perl said. But some facilities had trouble replenishing N95s as
supplies were used.

In addition,
there are concerns health care workers might be less vigilant about wearing the
N95 respirators since many perceive them to be less comfortable than medical
masks, such as making it harder to breathe and being warmer on the wearer’s
face.

Earlier
clinical studies comparing the masks and respirators yielded mixed results,
said Dr. Perl, also a Professor of Internal Medicine who holds the Jay P.
Sanford Professorship in Infectious Diseases.

The new
study was performed at multiple medical settings in seven cities around the
country, including Houston, Denver, Washington, and New York, by researchers at
the University of Texas, the CDC, Johns Hopkins University, the University of
Colorado, Children’s Hospital Colorado, the University of Massachusetts, the
University of Florida, and several Department of Veterans Affairs hospitals.
Researchers collected data during four flu seasons between 2011 and 2015,
examining the incidence of flu and acute respiratory illnesses in the almost
2,400 health care workers who completed the study.

The project
was funded by the CDC, the Veterans Health Administration, and the Biomedical
Advanced Research and Development Authority (BARDA), which is part of the U.S.
Health and Human Services Department and was founded in the years after Sept.
11, 2001, to help secure the nation against biological and other threats.

“It was a
huge and important study – the largest ever done on this issue in North
America,” Dr. Perl said.

In the end,
207 laboratory-confirmed influenza infections occurred in the N95 groups versus
193 among medical mask wearers, according to the report. In addition, there
were 2,734 cases of influenza-like symptoms, laboratory-confirmed respiratory
illnesses, and acute or laboratory-detected respiratory infections (where the
worker may not have felt ill) in the N95 groups, compared with 3,039 such
events among medical mask wearers.

“The
takeaway is that this study shows one type of protective equipment is not
superior to the other,” she said. “Facilities have several options to provide
protection to their staff – which include surgical masks – and can feel that
staff are protected from seasonal influenza. Our study supports that in the
outpatient setting there was no difference between the tested protections.”

Dr. Perl
said she expects more studies to arise from the data collected in this report;
she now plans to investigate the dynamics of virus transmission to better
understand how respiratory viruses are spread.

UT Southwestern, one of the premier academic medical centers in the USA, integrates pioneering biomedical research with exceptional clinical care and education.

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